TOPIC 3

ACTIVITY:
4 PIX 1 WORD
R
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C
K
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CRYSTALS
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SEDIMENTARY ROCKS
In our previous module, you have
learned that Geologists consider
Earth as a large functional system of
interacting spheres. These spheres
include the Lithosphere (the solid
body of the Earth), the Atmosphere
(the gas envelope surrounding the
Earth), the Hydrosphere (water in all
its forms at and near the surface of
the Earth), and the Biosphere (life on
Earth in all its forms and
interactions, including humankind).
ROCKS
and
Minerals
OBJECTIVES
At the end of this module, you will be achieving the following objectives:
 differentiate rocks from minerals,
 dentify common rock-forming minerals using their physical and chemical
properties (S11/12ES-Ia-9)
 classify rocks into igneous, sedimentary and metamorphic (S11/12ES- Ib10)
 describe how ore minerals are found, mined, and processed for human
use (S11/12ES-Ic-d-8)
 cite ways to prevent or lessen the environmental impact that result from
the exploitation, extraction, and use of mineral resources (S11/12ES-Id9).

Lasallian Core Value/s in Focus:

 Ensure that the learners translate knowledge into something useful in actual
practice for the betterment of the society and the Church.
 Discern with others the immediate and underlying causes as well as short- and
long-term effects of socio-environmental problems.
 May transform their learning into practical use for the betterment of society and
educate the uneducated.
What defines a
rock?
 A rock is an aggregate of one or more minerals,
or a body of undifferentiated mineral matter.
 Rocks contain clues, valuable information about
the environment in which they were formed.
 To geologists, a rock is a natural substance
composed of solid crystals of different minerals
that have been fused together into a solid lump.
The minerals may or may not have been formed
at the same time. What matters is that natural
processes glued them all together.
What branch of
geology deals with the
study of rocks?
 Petrology is a branch of geology that
focuses on the origin, composition,
structure, and classification of rocks. It
involves examining the physical and
chemical properties of rocks to
understand their formation processes
and geological history. There are
different subfields within petrology that
focus on specific types of rocks, such as
igneous petrology, sedimentary
petrology, and metamorphic petrology.
 Petrologist a geologist who unravel and
interpret that information.
 Igneous rock is formed as a
result of the hardening of lava or
magma (molten rock).
 Igneous petrology involves the
study of the origin and nature of
magma. Igneous petrology also
involves the identification,
classification, origin, evolution,
and processes of formation and
crystallization of igneous rocks.
 Metamorphic rock
 “meta” means “change” and
morphis” means “forms” in Greek.
 rocks that have changed due to
temperature and pressure.
 Igneous, sedimentary and other
metamorphic rocks can change to
become metamorphic rocks.
 Metamorphic petrology is the study
of all rocks that are formed by
crystallization in the solid state,
beyond the field of diagenesis.
 Sedimentary rock
 formed by weathering and erosion.
 are moved from place to another.
 are deposited in the older ones on the
bottom.
 the layers become compacted or
cemented together.
 Sedimentary petrology studies the
mineralogical and geochemical
composition of sediments and
sedimentary rocks to determine
depositional and post-depositional
processes of formation.
The rock cycle is a web of processes
that outlines how each of the three major
rock types—igneous, metamorphic, and
sedimentary—form and break down
based on the different applications of
heat and pressure over time.
 Igneous rock can change into
sedimentary rock or into
metamorphic rock.
 Sedimentary rock can change
into metamorphic rock or into
igneous rock.
 Metamorphic rock can change
into igneous or sedimentary rock.
Minerals:
Properties and
Types
Mineral
 means a naturally-occurring inorganic
element or compound having an orderly
internal structure and a characteristic
chemical composition, crystal form, and
physical properties.
 They serve as fragments and turn into rocks
if mixed with each other.
 Minerals are the building blocks of rocks.
Nature cements combinations of minerals
together to form rocks.
Mineralogy
 is
a
branch
of
geology
specializing in the scientific study
of the chemistry, crystal structure,
and physical properties of
minerals
and
mineralized
artifacts.
PROPERTIES
This hardness scale was designed by
German geologist/mineralogist Friedrich
Mohs in 1812 (Mohs Scale of Hardness).
The Mohs Scale of Hardness measures the
scratch resistance of various minerals from a
scale of 1 to 10, based on the ability of a
harder material/mineral to scratch a softer
one.
Pros of the Mohs scale: (advantage)
i. The test is easy.
ii. The test can be done anywhere,
anytime, as long as there is sufficient light to see
scratches.
iii. The test is convenient for field
geologists with scratch kits who want to make a
rough identification of minerals outside the lab.
Cons of the Mohs scale: (disadvantage)
i. The Scale is qualitative, not
quantitative.
ii. The test cannot be used to
accurately test the hardness of industrial
materials.
Specific Gravity– the ratio of the density of the mineral/substance and the density
of
water.
a. This parameter indicates how many times more the mineral weighs compared to an
equal amount of
water (SG 1).
b. For example, a bucket of silver (SG 10) would weigh ten times more than a bucket
of water.

Others– magnetism, odor, taste, tenacity, reaction to acid, etc.

For example, magnetite is strongly magnetic; sulfur has distinctive smell; halite
is salty; calcite fizzes with acid as with dolomite but
in powdered form; etc.
TYPES
Metallic Minerals
Metallic minerals exhibit luster in their appearance and consist of metals in their
chemical composition. These minerals serve as a potential source of metal and can
be
extracted through mining.
 Ferrous minerals are one that contains iron.
 non-ferrous are one that does not contain iron.
Non-metallic Minerals
Non-metallic minerals are minerals which either show a non-metallic
luster or shine in their appearance. Extractable metals are not present in
their chemical composition. Limestone, gypsum, and mica are examples
of non-metallic minerals.
Formation,
Mining and Its
Uses
Process

Description

Minerals that form this way

Evaporation

When a body of salt water dries up,

minerals areleft behind. As the water
evaporates, the minerals crystallize.

gypsum, halite

Metamorphism

High temperatures and pressures deep

below
the ground can cause the minerals in
rock to change into different minerals.

garnet, graphite, magnetite, talc

Deposition

Surface water and ground water carry

dissolved minerals into lakes or seas.
The minerals can crystallize on the
bottom of the lake or sea.

calcite, dolomite

Reaction

Water underground can be heated by

hot rock. The hot water can dissolve
some minerals and deposit other
minerals in their place.

gold, copper, sulfur, pyrite, galena

Cooling

Melted rock can cool slowly under

Earth’s surface. As the melted rock
cools, minerals form.

mica, feldspar, quartz

How are minerals
removed from the
earth?
Many kinds of minerals are being mined from
the ground and people make them into
objects we need and use. Some minerals
have more useful materials in them than
others.
An ore is a rock or mineral that contains
enough useful materials for it to be mined at a
profit.
There are two ways of removing ores from
Earth: surface mining and subsurface
mining. The type of mining used depends on
how close the ore is to the surface.
I. SURFACE MINING

 Open-pit mining is used to remove large, near-surface deposits of gold and

copper. Explosives break up the rock layers above the ore. Then, trucks haul the
ore
from the mine to a processing plant.
Largest global open-pit mines by depth:
As of 2023, the Bingham Canyon mine in
Utah, United States, was the deepest open-pit
mine in the world, with a depth of more than
1.2 kilometers. Bingham Canyon was
established in 1906 as a copper mine, and is
the world's largest excavation made by
humans.
 Quarries are open mines that are used to remove sand, gravel, and
crushed rock. The layers of rock near the surface are removed and used
to make buildings and roads.
 Strip mines are often used to mine coal. The coal is removed in large pieces.
These pieces are called strips. The strips of coal may be up to 50 m wide and
1 km long.
II. SUBSURFACE MINING
People use subsurface mining to remove ores that are deep underground. Iron, coal,
and salt can be
mined in subsurface mines.
QUESTIONS???
Is there a mineral
harder than a
diamond?
Now, theoretical work by researchers
in China and the US suggests that
pure wurtzite Boron Nitride (wBN)
18% strongers is significantly harder
than diamond. They also predict that
Lonsdaleite — with a structure
closely related to wurtzite — could
be transformed under pressure to
become 58% harder than diamond,
a new world record.
wurtzite Boron Nitride (wBN)

Lonsdaleite